


All that sexual tension

by soy_em



Series: Wincestmas 2017 [2]
Category: Supernatural
Genre: De-Aged Sam Winchester, M/M, Spells & Enchantments
Language: English
Status: Completed
Published: 2018-01-07
Updated: 2018-01-09
Packaged: 2019-03-01 17:58:44
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 3,878
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13300227
Author URL: https://archiveofourown.org/users/soy_em/pseuds/soy_em
Summary: Rowena is sick of those Winchesters hunting her down. She needs something to distract them... maybe if they finally act on all that sexual tension buzzing around them they'll leave her alone.





	1. Chapter 1

**Author's Note:**

  * For [SinnamonSpider](https://archiveofourown.org/users/SinnamonSpider/gifts).



There’s a bang and the motel door flies open. Dean’s on his feet immediately, scrambling for his gun even as he assesses the threat. 

Sam tumbles into the room, literally ass-over-tea-kettle, long legs flying over his head as he rolls to a stop at Dean’s feet. Dean’s hand shivers as he trains the gun on the open doorway, waiting to see what’s wrong; but nothing follows Sam into the room. There’s just the quiet echoing of an empty motel parking lot and the whuffing breaths coming from his little brother. 

When Dean finally looks down, his rapidly pounding heart freezes. Sam looks up at him out of eyes big in a rounded face, hidden under shaggy bangs that Dean hasn’t seen in over fifteen years. His skinny chest is heaving, long twig legs sprawling out from his body in clothes that are swimming on his slender frame. Sam had only gone out to get their morning coffee, and he’s come back _like this._

“What _the fuck,_ Sammy?” Dean demands.

***

“Rowena,” is Sam’s terse answer when he gets his breath back, in a voice far higher than Dean’s accustomed to. 

“Rowena is the witch we’ve been following?” 

“Yeah. And she saw me from across the road, I guess, and well…” Sam tails off, gesturing down at himself. 

“Well.” Dean echoes. He can’t quite process what’s happened.

Sam unfolds himself, standing up to his full height. Which, Dean notices with a swoop of his stomach, is a little less than Dean himself. 

“How old are you meant to be, anyway?”

Sam frowns, nose wrinkling, and shoves his bangs out of his eyes. He comes to stand in front of Dean, close enough that his warm, sweet breath brushes against Dean’s cheek. He’s just smaller, just enough that he has to tip his eyes up to look at Dean. “Um… about 18, I guess?” 

“How’d you know?” 

“I got taller than you just after-” he pauses, ducking his head.

 _Just after I left for Stanford,_ Dean fills in mentally. They still don’t talk about it. Dean can still remember the shock, that night in Sam’s Stanford apartment, when Sam had stood up and towered over him for the first time.

“Ok.” He takes a deep, deep breath, trying to right his thoughts. “We got two choices: try and go after Rowena, or try and fix this ourselves.”

“She’ll be long gone,” Sam suggests. “Now that she knows we’re onto her.”

Dean hums, sorting through everything they know about Rowena. “I’m not so sure,” he says slowly, thinking aloud. “I think she’ll wanna stick around and laugh at us.”

The flash of annoyance across Sam’s face is at once so familiar and utterly disconcerting. Now, that look tends to be directed at Rowena, at Crowley, at their current case; back when Sam had this body, it had been directed at everything as teenage Sam had vented his frustrations. Their Dad and the life they led had been a frequent recipient of Sam’s disgust, but Dean hadn’t avoided it either, and it’s an unpleasant reminder of their teenage arguments. 

“Yeah, you’re right. Guess we better try find her.”

***

That’s harder than Dean could have imagined. Not just because Rowena is tricky and cunning - if she wants to stay hidden, she’ll find a way - but because Sam doesn’t look like an FBI agent anymore. Or like any of their other typical disguises. He doesn’t even look like a credible intern. They have to beat a hasty retreat from the police station when the local sheriff starts asking too many questions, and the bouncer won’t even let Sam into bar where Rowena had last been seen.

“Just go back to the motel, Sammy,” Dean says, gritting his teeth. Today has been harder on him than he’s willing to admit; Sam’s outward appearance a constant reminder of feelings he’d ruthlessly squashed down when Sam had run away.

“No, I’m going to help,” Sam insists, jaw set. His skinny wrists poke out from under the cuffs of his shirt, but his trousers are pooled around his ankles where his legs aren’t quite as long as they should be. The shirt billows around his chest - he’d pulled the suit jacket off as soon as he could, unable to function properly with the longer sleeves - and every time he moves, Dean catches a glimpse of smooth, hairless chest. “I’ve spent more time with her than you, I know how she thinks.”

“There’s nothing you can do,” Dean insists, trying to make his argument sound believable even to himself, when all he actually wants is to remove the temptation that is Sam from his sight for a little while. “I can investigate easier by myself. Then I’ll come back and tell you everything, and you can use your great wisdom and knowledge to predict what she’ll do next.” 

Sam scowls at the sarcasm in his voice. “Fine.” He spins on his heel and stomps off, the dramatic exit only barely ruined by his little stumble as he narrowly avoids a lamppost. Sam at eighteen had been all new angles, long legs and clumsiness, and that’s clearly true of Sam at thirty-four in his old body. 

Dean breathes freely for the first time since Sam had re-appeared in their motel room that morning. Taking a moment, he leans back against the wall outside the bar, closing his eyes. 

Images of Sam flash through his brain - images of Sam today overlaid with images of Sam when he really was eighteen, when he’d taken to wearing little shorts and loose t-shirts that hung off his shoulders. When he’d taken to stealing Dean’s old t-shirts, squeezing new muscle into old material; and when he’d often spent long hours in the shower, high noises spilling out that Dean had tried so hard not to hear. 

There’s a million reasons they still don’t talk about Stanford; and one of them is the reason Dean had let Sam go. His sanity had been hanging by a thread when Sam had revealed his plan; he’d barely been able to think at times for how much he’d wanted his little brother and how guilty he’d felt. He’d often head out to bars, ready to drink himself into forgetfulness; but come home without touching a drop, suddenly terrified that he’d lose his inhibitions with his sobriety. 

Sam had wanted - expected - Dean to come with him to Stanford. That had been painfully apparent in the triumphant way he’d revealed his plans to their father, vicious satisfaction evident in his voice as he’d expected to announce his victory in their years-long push-pull fight over Dean’s affection, Dean’s loyalty. But Dean had steeled himself and turned Sam down; insisting that hunting was his life, that there were people to save. Sam had turned doe eyes swimming with tears on him, but Dean had stood firm. Their father’s joy at winning had led to the savage fight that saw Sam banished from the family for so many years. 

Since then, Dean has managed to restrain his feelings, pushing them to a place where he barely remembered they existed. Winchesters were masters of denial, after all. But now, everything is bubbling to the surface again. 

Scrubbing his hand across his eyes, he pushes himself away from the wall and heads into the bar. Time to get back to work, to find Rowena and find a cure - and then he can go back to forgetting he’d ever had inappropriate, dirty thoughts about his little brother.

***

Dean makes his way back to the motel a couple of hours later, tiredness singing through his body. It’s mental tiredness more than anything - weariness from trying to suppress his feelings all day - and all he wants is a burger, a beer and a quiet night. 

Takeaway bag in hand, he nudges the door open with his hip, hoping that Sam isn’t going to kick up a fuss about the unhealthy food. His worries go to shit when the bag crashes to the floor, spilling fries everywhere; the cola pooling across the already-stained floor. 

Sam’s stretched out on the bed, face down. He’s completely naked, muscles fluttering as he rolls his hips back to meet the three fingers stretching his ass wide, and his face is buried in the t-shirt Dean was wearing yesterday.


	2. Chapter 2

Sam’s feeling stroppy when he heads back to the motel - that’s the only way to describe it. He knows Dean is right, that it will be easier for him to find answers without an eighteen-year old partner causing concern; but that doesn’t make it any easier to stomach. Part of it is that they have unfinished business with Rowena (who don’t they have unfinished business with?), but most of it is just general annoyance.

It takes him most of the long walk back to realise that maybe his annoyance is out of proportion to the situation, but once he does, everything clicks. “Goddamn hormones,” he thinks. No wonder he feels so grumpy. His body is eighteen years old again and at that age, Sam had been angry almost constantly. (Or horny, but perhaps it was best not to think about that...)

Arriving back at the room, he throws himself down on the bed, his smaller body bouncing up from the sheets in a way he hadn’t anticipated. He knows he should get out his laptop, do some research on the spell Rowena might have used and try to find a counter-spell, but he just _can’t be bothered._ He’s the main victim him here, after all - sure, they’d been tracking a witch anyway, but no one had been dying. So if he chooses to take an hour’s break, that’s his own choice.

Instead, he lies back, hands pillowed behind his head, and goes back to his old teenage pastime of staring at the stains on motel ceilings. 

Sam wonders what Dean had made of today. He’d been shocked at first, of course - even for the Winchesters, this kind of spell is rare enough to be noteworthy. But he’d seemed to settle very quickly and take it in a stride; he hadn’t really seemed worried about Sam or disconcerted by his new appearance at all. 

Sam glances down his body, looking at where his skinny torso descends into thin, stick-like legs that turn into bony feet. He hates this body. He’d hated it so much at the time that he’d often stared into mirrors for hours, prodding at himself, wondering how he could change it. He’d been forced to spend hours listening to Dean raving about women, after all; how pretty they were, how soft, how curvy. His own body was nothing like that, all angles and sharp edges, and he’d known that it was part of the reason Dean would never look at him the way he craved. Despite that knowledge, he’d done everything he could to challenge his brother. He’d crammed himself into too-tight clothes, draped himself provocatively over furniture, walked around half naked and even resorted to trying to provide free live porn for his brother in the shower, but nothing had caused even the slightest flicker of recognition in Dean’s beautiful eyes. 

And then Dean had turned him down and he’d gone to Stanford alone. That had been a bit of a revelation for him - men there had loved his body; he’d hooked up more than he could ever have imagined before he’d met Jess and settled down, and he’d revelled in it. The confidence boost had been much needed, but it had all come crashing back down when he’d gone back on the road with Dean.

Sam had hoped, almost prayed, for just the slightest flicker of desire behind Dean’s eyes back then, but when nothing had been forthcoming, he’d tried a different tack. His body had finally stopped growing and he’d found himself able to really put on muscle for the first time, so he’d worked out, hard, in the hope that Dean would be more attracted to a muscular-Sam. It hadn’t worked, of course - Dean had remained as oblivious as ever. But Sam himself had preferred his body bigger, and it had been better for hunting, of course; so he’d kept up the exercise ever since.

Sam’s been able to squash his unnatural feelings for Dean for a while now; concentrating on the true goodness, the strength, of their fraternal bond. But he’s never really gotten over his hatred of his skinny-boy body, and the rush of feelings today has brought back is wholly unwelcome. 

He groans in frustration, tossing his head back on the pillow. Why on earth does he have to be cursed with these feelings for his big brother? Has he not had enough other shit thrown at him in his life? It’s so _unfair._

The maelstrom of feelings coursing through him focuses on one thing: Dean. (The only thing it ever focuses on, if Sam’s being totally honest.) Sam had forgotten what it felt like to have to look up at Dean until today; had forgotten how much he’d loved it as a teenager. 

When he’d tipped his head back to look at Dean this morning, under the guise of comparing their heights, it had been… a revelation. He’d secretly adored being smaller than Dean back then, had loved the thought that Dean would be able to throw him around, and Dean now is just so much bigger than he could ever have imagined when he was seventeen. If he’d thought Dean was strong back then, he can barely imagine what Dean could do to him now. 

Except apparently he can imagine it, because images start flying through his mind and his cock starts to harden faster than he’d thought possible. He groans, knowing that he shouldn’t; that he should get up, have a cold shower and get on with his research. But he slides his hand down his chest, just once, catching at a nipple as he goes; and that’s it - all restraint goes out of the window. He’s suddenly rock hard, as desperate for Dean to touch him as he’s ever been; and dammit, he’d forgotten how different it was being a teenager compared to being thirty four. 

Shucking his trousers quickly, he rationalises that he’s got at least an hour, probably far more, before Dean comes home. More than enough for what his teenage body needs (he seems to remember that he could go multiple times an hour back then). So he pulls his shirt off as well, and settles back. 

His mind is filled with Dean. He knows Dean’s body so well, so intimately, that it takes almost no effort to imagine those strong arms bracketing him; those thick thighs pushing and straining against his own. He sees Dean’s freckled nose right above him, can almost feel Dean’s sharp white teeth closing on his neck and further down. He pulls sharply at a nipple, imaging Dean’s capable hands twisting his nipples back and forth, and finally reaches his cock, giving it a quick tug. 

There’s something missing though; something he used to do all the time as a teenager but hasn’t done in years. Spotting Dean’s t-shirt lying on his unmade bed, he snatches it up and presses it to his face. Dean’s scent immediately washes over him, comforting and arousing in equal measure. 

Sam’s hand moves frantically over his cock, but its not enough. He pauses for a moment before standing on wobbly legs and heading into the bathroom, snagging the small tube of free lotion this better-than-usual motel had left for them. He hasn’t done this for a long time, not since he’d given up any hope of being with Dean; but today seems to be all about old routines. 

Back on the bed, he turns onto his front and slicks his fingers up quickly. Heart racing, he reaches back and circles his hole quickly, spreading the lotion about. Then, with a deep breath, he pushes his finger inside, imagining a much thicker digit in place of his own. “Dean,” he murmurs, finding it even easier to imagine his brother behind him now that the way he’s got his face mashed into Dean’s shirt is shutting out the light. “Please.”

He quickly adds a second finger, gasping at the stretch which is still so familiar. He starts to roll his hips back onto his fingers, lightning shooting through his veins as he feels absolutely filthy. 

He doesn’t even hear the door open behind him.


	3. Chapter 3

Dean’s brain doesn’t know what to do with the image before him. It’s every repressed, and not so repressed, fantasy he’s ever had coming to life in front of him.

“Sammy?” he stutters, but his voice is barely more than a whisper, and Sam doesn’t respond. Dean grips the door frame, for once in his life completely frozen.

Sam’s got three fingers in his ass, he notes almost disbelievingly. He’s rocking back again and again onto three fingers, even though his body is so much smaller than it was this morning. And he looks like he loves it. 

He should go. He should ignore the fact that Sam’s clutching his t-shirt in his sweaty, trembling hand - surely just coincidence - and he should leave Sam to his private time.

“Dean, please.”

For a painful moment, Dean’s sure that Sam’s spotted him, is begging Dean to go and leave him with some dignity. 

But then he realises that Sam’s face is still pressed into the mattress, and there’s no way he could’ve seen Dean. He’s deliberating what Sam could mean by it when Sam speaks again.

“Dean,” he whines, voice drawn out so that its almost a moan, high pitched and needy; and Dean can’t deny it any longer. Sam is calling out for him.

He crosses the room slowly, steps still hesitant despite everything. He keeps his eyes on Sam, drinking in the body he’d wanted for so long.

“Sammy,” he says again, when he reaches the bed. “Sammy.” Sam’s so completely gone, though; that he just whimpers. Dean can’t help himself, he winds his hands into Sam’s sweaty hair and tugs Sam’s head up. 

“Dean!” Sam looks up at him, eyes unfocused. “Wish you were real,” he mumbles. 

Dean can’t resist any longer. “I am real,” he insists, before swooping down to kiss his brother. The angles all wrong, Sam’s face still pressed into the bed, but it’s the best kiss Dean has ever had. 

Sam’s panting when Dean breaks away, still dazed. 

“Tell me you want this,” Dean demands. “Sam, tell me you want this.”

“Always wanted this,” Sam says, huge eyes earnest. 

Dean doesn’t waste any more time. Somehow, his greatest wish is coming true; he’s not going to risk losing it. He carefully grabs Sam’s wrists, pulling them both up so that they’re level with his head, and then flips Sam easily, so that he lands on his back. Crawling over his brother, he starts pulling his own clothes off, tossing them haphazardly around the room. 

“Do you really want this too?” Sam asks, wonderingly. He’s peering up at Dean from underneath those ridiculous bangs. He looks so young and vulnerable that Dean’s heart clenches, even though he knows that Sam’s still his real age. 

“Always wanted this,” he echoes, and Sam sighs, relaxing back against the pillows for a moment. But it only lasts a second, before his hands are in motion, covering all of Dean that he can reach; desperately touching across Dean’s shoulders and chest, down towards Dean’s hips. 

Dean lets him touch, enjoying the feeling in an abstract way as he shifts Sam to his liking. Within seconds, he’s got a pillow under Sam’s hips, tilting his brother’s hips up and spreading his legs. Sam goes so easily, and Dean can soon see the shine of where he’d been touching himself, before. 

A quick touch ascertains both that Sam doesn’t need further prep, and also that he’s ridiculously sensitive there. His body jumps, back bowing off the bed even from the light touch, and Dean has to circle his fingers around the base of his own cock to stop things from ending too early. Sam’s hands grab him and drag him forwards, his brother beyond words but still somehow able to indicate exactly what he wants. 

“You sure, Sammy?”

“Just fuck me, Dean, please.”

Dean doesn’t need any more encouragement. He barely spares a moment to think of a condom and then brushes the thought aside; he got tested a couple of months back and hadn’t hooked up since. He and Sam live in each other’s pockets, he’d know if Sam had had sex recently. They’re fine. And if not, they know an angel who would no doubt heal them both just to avoid hearing about how they’d both gotten the same STI. 

Once that last practical thought is brushed aside, all his doubts disappear. This is right, this is meant to be, he thinks inanely as he slides into Sam; the tight, wet heat of his little brother clearly scalding the cynicism right out of his brain. “Shit, Sammy,” he pants, ducking his head down to kiss his brother, and Sam meets him halfway, back bowing as he strains up towards Dean. 

Sam’s insistent rocking forces him to set a hard pace right from the beginning, Sam slamming his hips up to meet Dean’s with every thrust. Dean curves his arm under Sam’s back, taking advantage of Sam’s slighter form to bring them as close together as it’s possible to be while he feels Sam shake apart. 

“Dean, Dean, Dean,” Sam chants, nails digging into Dean’s shoulders as he trembles, slender legs flexing around Dean’s hips and cock rubbing against Dean’s stomach. Dean barely has time to get a hand down and give Sam a couple of quick, uncoordinated strokes before his brother is coming with a shout, teeth biting sharp into Dean’s shoulder. 

Dropping Sam back onto the bed, Dean moves faster, chasing his own orgasm before Sam gets too sensitive. Sam clenches around him as he comes down, and that, along with the blissed-out joy on his brother’s face, is enough to send Dean over the edge himself, pumping into Sam with a joyous feeling of possessiveness as he fills his brother. 

Dean stays crouched over Sam for a few seconds longer, revelling in the sight of Sam underneath him, something he’d dreamed about for so long, but eventually he rolls off to the side. Sam immediately tucks himself into Dean, this smaller body fitting neatly under Dean’s chin in a way Sam won’t once they find a way to restore his normal body.

“Please don’t hate me,” Sam says in a small voice, directly into Dean’s collarbone. 

“I could never hate you,” Dean says, completely sincere. “I can’t even hate Rowena, since she’s given us this.” 

Sam’s laughing even as his eyes slip shut.

*** 

Neither of them spot the red-headed witch outside the window. That little something extra she’d added to her de-aging spell to lower Sam’s inhibitions had really paid off. Hopefully now that the Winchesters have acted on all that sexual tension swirling around them, they’ll be too far occupied with each other to even think about hunting down any witches. Rowena presses her nose against the glass as she grins and enjoys the show.

**Author's Note:**

> Come check out my [Tumblr](https://soy-em.tumblr.com/).


End file.
